Messages in this thread Patch in this message | | | From | Jose Abreu <> | Subject | [PATCH net] net: phy: Don't assume loopback is supported | Date | Thu, 14 Mar 2019 11:37:21 +0100 |
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Some PHYs may not support loopback mode so we need to check if register is read-only.
Fixes: f0f9b4ed2338 ("net: phy: Add phy loopback support in net phy framework") Signed-off-by: Jose Abreu <joabreu@synopsys.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Joao Pinto <joao.pinto@synopsys.com> --- drivers/net/phy/phy_device.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 49fdd1ee798e..a749639d98c3 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -1918,8 +1918,24 @@ EXPORT_SYMBOL(genphy_resume); int genphy_loopback(struct phy_device *phydev, bool enable) { - return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, - enable ? BMCR_LOOPBACK : 0); + int ret; + + ret = phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, + enable ? BMCR_LOOPBACK : 0); + if (ret < 0) + return ret; + + ret = phy_read(phydev, MII_BMCR); + if (ret < 0) + return ret; + + if (enable) { + if (ret & BMCR_LOOPBACK) + return 0; + return -EOPNOTSUPP; + } + + return 0; } EXPORT_SYMBOL(genphy_loopback); -- 2.7.4
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